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选用食用型甘薯品种‘泰中6号’为材料,以正常灌水处理为对照,研究干旱胁迫下外源喷施脱落酸(ABA)对甘薯叶片光合特性及相关生理指标的影响。结果表明:干旱胁迫使甘薯叶片脯氨酸、过氧化氢(H_2O_2)、丙二醛(MDA)含量增加,外源ABA处理能减少MDA的积累,使其含量处于较低水平。外源ABA能够提高叶片净光合速率(P_n),降低气孔导度(G_s)和蒸腾速率(T_r),提高水分利用效率(WUE)。ABA处理能防止叶绿素降解并对干旱引起的最大光能转化效率(F_v/F_m)、实际光化学效率(ΦPSII)、光化学猝灭系数qP下降及非光化学猝灭系数(NPQ)升高有明显的缓解作用。干旱胁迫下,H_2O_2的积累伴随着具有抗氧化作用的SOD和POD酶活性的提高,而ABA处理能增加H_2O_2的积累,并进一步提高这些酶的活性。干旱胁迫下,外施ABA能增强甘薯的抗氧化防护系统,提高水分利用效率,提高甘薯的抗旱性。正常灌水条件下外施ABA对甘薯生长前期叶片生理特性的影响作用不显著。
The edible sweet potato variety ’Taizhong 6’ was selected as the material, and the normal irrigation treatment was used as the control to study the effects of abscisic acid (ABA) on photosynthetic characteristics and related physiological indexes of sweet potato under drought stress. The results showed that the contents of proline, hydrogen peroxide (H 2 O 2) and malondialdehyde (MDA) in leaves of sweet potato increased under drought stress. Exogenous ABA treatment could reduce the accumulation of MDA and lower the content of MDA. Exogenous ABA increased leaf photosynthetic rate (P_n), decreased stomatal conductance (G_s) and transpiration rate (T_r) and increased water use efficiency (WUE). ABA treatment could prevent chlorophyll degradation and significantly alleviate the maximum light energy conversion efficiency (F_v / F_m), actual photochemical efficiency (ΦPSII), decrease of photochemical quenching coefficient qP and non-photochemical quenching index (NPQ) induced by drought. effect. Under drought stress, the accumulation of H 2 O 2 was accompanied by the increase of SOD and POD activities, while ABA treatment could increase the accumulation of H 2 O 2 and further enhance the activity of these enzymes. Under drought stress, the application of ABA can enhance the antioxidant defense system of sweet potato, improve water use efficiency and improve the drought resistance of sweet potato. Under normal irrigation conditions, ABA had no significant effect on the physiological characteristics of leaves at the early stage of sweet potato growth.